Assuming that you want constant (or at least high) speed motion along a
path you need to consider the energy requirements to make your mobile
follow the path.

The first implication is that in theory you can't turn ANY corner (no
matter what angle) precisely without stopping completely at the corner
point, if the mobile has mass and your energy source is limited in power
(both are usually true).

In most cases this is too slow so one makes compromises and only slows
down for angles above a certain value, to accomodate braking on the other
axis.

The easiest way is to over-engineer the drive and mechanism and simply run
at constant speed all the time knowing that any axis can stop/start in 1
unit step. This is expensive and inefficient for most real uses, so it is
only used by hobbyists and cheap consumer equipment makers ;-).

Peter

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